import edu.princeton.cs.algs4.Bag;
import edu.princeton.cs.algs4.StdIn;
import edu.princeton.cs.algs4.StdOut;

public class Stats {
  public static void main(String[] args) {
    Bag<Double> numbers = new Bag<Double>();
    while (!StdIn.isEmpty()) {
      numbers.add(StdIn.readDouble());
      int N = numbers.size();
      double sum = 0.0;
      for (double x : numbers) {
        sum += x;
      }
      double mean = sum / N;
      sum = 0.0;
      for (double x : numbers) {
        sum += (x - mean) * (x - mean);
      }
      double std = Math.sqrt(sum / (N - 1));
      StdOut.printf("Mean: %.2f \n", mean);
      StdOut.printf("Std dev: %.2f", std);
    }
  }
}
